Auxiliary protein of DNA polymerase delta and is involved inthe control of eukaryotic DNA replication by increasing thepolymerase's processibility during elongation of the leading strand. Induces a robust stimulatory effect on the 3'-5' exonuclease and 3'-phosphodiesterase, but not apurinic-apyrimidinic (AP) endonuclease, APEX2 activities. Has to be loaded onto DNA in order to be able tostimulate APEX2. Plays a key role in DNA damage response (DDR) by beingconveniently positioned at the replication fork to coordinate DNAreplication with DNA repair and DNA damage tolerance pathways. Acts as a loading platform to recruit DDR proteinsthat allow completion of DNA replication after DNA damage and promotepostreplication repair: Monoubiquitinated PCNA leads to recruitment oftranslesion (TLS) polymerases, while 'Lys-63'-linked polyubiquitinationof PCNA is involved in error-free pathway and employs recombinationmechanisms to synthesize across the lesion. [1-4]

MFEARLVQGSILKKVLEALKDLINEACWDISSSGVNLQSMDSSHVSLVQLTLRSEGFDTYRCDRNLAMGVNLTSMSKILKCAGNEDIITLRAEDNADTLALVFEAPNQEKVSDYEMKLMDLDVEQLGIPEQEYSCVVKMPSGEFARICRDLSHIGDAVVISCAKDGVKFSASGELGNGNIKLSQTSNVDKEEEAVTIEMNEPVQLTFALRYLNFFTKATPLSSTVTLSMSADVPLVVEYKIADMGHLKYYLAPKIEDEEGS